Worst Theory, Ever

In 1979 a pair of researchers set out to test the idea that depressed individuals suffer from a flaw in their perception of the world. Instead, their experiment uncovered results for participants in a rigged game set-up showed the depressed individuals provided more accurate self-assessments.
The theory is called "depressive realism" and implies people are "sadder but wiser" because the depressed possess a more accurate perception of reality. The theory is counter-intuitive, but as recently as 2012, researchers using more sophisticated tools like fMRI still found:

Depressed patients showed a more balanced attribution pattern consistent with depressive realism (Moritz et al., 2007). This group difference showed that depressed patients do not see the world through the proverbial “rose-coloured glasses” associated with self-serving tendencies in controls. Indeed, those with the greatest symptom severity exhibited a negative attribution bias. The negative correlation of the percentage of self-serving attributions and depressive symptom severity shows that with increasing symptom severity, depressive realism turns into a frankly non self-serving tendency. In contrast, controls are happily self-serving and those with more self-serving attributions also reported the greatest self-esteem.

The idea that the only people that see things for what they are become depressed and the rest of us are just gullible enough to feel good regardless of the reality around us. While there are an abundance of efforts to link happiness to performance, including Norman Vincent Peale positive thinking, The Secret positive force,  and countless motivational speakers, the notion that unhappiness is a by-product of improved perception is a rather unpleasant supposition that almost poses that depression is justifiable. I hope that is as revolting a theory to you as it is to me. I have to wonder if the absurdity actually suppresses experimentation to counter the work supporting depressive realism. There are of course some studies that do so, but probably not enough to bury the theory as soundly as the demise of flat Earth theories.

Some ideas on explaining the experiments without buying the theory:

• people have a tendency to believe their success was their doing, but blame failures on external forces (self-serving bias)
• people have a tendency to believe the success of others was due to external forces, but believe their failures were their doing (fundamental attribution error)
• depressed people do the opposite of most people, believing their success came from external factors and their failures were their doing, and believing the success of others was their doing but failure of others were from external forces
• depressed people may include less contextual information when perceiving reality, so the more limited in focus the situation the more likely depressed people are to be accurate than the rest of people who are inclined to include more information when perceiving situations